Follow-up mechanism for indicating devices



Sept. 23, 1941.

E. BAUMANN FOLLOW-UP MECHANISM FOR INDICATING DEVICES Filed March 24,1939 INVENTOR 5, Ba, a 07 a; 17 /7 ATTORNEY Patented Sept. 23, 1941FOLLOW-UP MECHANISM FOR INDICATING DEVICES Ernst Baumann, Berne,Switzerland, assignor to Hasler A.-G. Werke fiir Telephonie undPrazisionsmechanik, Berne, Switzerland, a corporation of SwitzerlandApplication March 24, 1939, Serial No. 264,046 In Switzerland March 31,1938 7 Claims.

The invention relates to a follow-up mechanism in an indicating deviceparticularly in a device for indicating and recording the chargingpressure of an internal combustion engine in relation to the tachometer.

According 'to the invention a flexible diaphragm or composite diaphragmis exposed to the fluid pressure to be recorded and moves a member inthe path of an oscillating driver actuating the recording mechanism, sothat the travel of the driver, in one direction, is variably limited bythe said moving member. The action of the recording mechanism is,consequently, dependent on the fluid pressure, but that pressure is notused for actuating the recording mechanism.

An example of apparatus according to the invention is shown in theaccompanying drawing, in which Fig. 1 is a vertical section thereof,partly broken away, and.

Fig. 2 is a perspective view of the follow-up mechanism.

The casing I shown in the left hand side of Fig. 1, partly broken awayis divided by a horizontal partition 2 into two chambers 3 and 4. Theupper chamber 4 contains the recording device, which may be of anyconvenient construction, and of which only the record sheet 5 is shown.Mechanism for actuating the recording implement is contained in thechamber 3. The record sheet 5 may be moved at a constant speed, e. g. bymeans of a clockwork, or at a speed varying with that of a drivingshaft, e. g. the axle of a vehicle, according to the purpose for whichthe instrument is used.

Joined to the casing l is a cylindrical casing 6. The dividing wallbetween the casings has an opening 23 with a circular cover I on oneside and a cover 22 on the other side, and opposite this opening thecasing 6 has an opening with a gas-tight cover 8, held in position by ascrew ring 9. The cover 8 has an inwardly directed recess, and outsideit there is an external cover I!) with an outwardly directed recessforming a compartment II, in which there are two bevel gears l2, l3 fordriving spur gears l4, IS in the cavity in the cover 8. A nipple I6 isscrewed into the upper part of the cover In, and projects through thecover 8. This nipple serves for joining the pressure pipe to theinstrument. This may, for example, be a pipe connected to the inductionpipe of an internal combustion engine. The pocket II has a tubularextension l0 with a gland I'l therein for a shaft l8 carrying the gearl2. The shaft has a gudgeon IQ for coupling therewith a driving shaft,which may for example be driven by the axle of a vehicle. The gears l3and I4 are fixed to a shaft passing through a hollow shaft 2| betweenthe covers I and 8. Between the covers 1 and 22 this shaft drives theactuating mechanism of a speedometer, not shown in the drawing.

The gear wheel I5 is fixed to a shaft 25, which carries inside thecasing 6 a disk 26, which carries a cam roller 27. Supported by a bar 28in the casing 6 are two elastic diaphragm boxes 29, but there may bemore than two such boxes. A link 36 connects the bottom of the lower boxto an arm 3| on a shaft 32 mounted in bearings in the covers 1 and 3,and to this shaft is fixed also a curved arm 33 having a finely serratedconvex edge. A detector lever 34 mounted on sleeve 52 on shaft 38 has alaterally projecting tooth 35 in the path of the curved arm 33 and alever 31 also mounted on sleeve 56 is held by a spring 36. in contactwith the roller 21, so that at intervals the detector lever 34 isremoved from contact with the curved arm 33, and the tooth 35 isdisengaged from the serrated edge of that arm, which is thus enabled toassume a new position if the fiuid pressure has changed.

The shaft 38 parallel to shaft 25 has a toothed quadrant 39 fixedthereto, and a coiled spring 40 acts on this quadrant so that when thequadrant is released from a detent to be described hereinafter it isrotated till an abutment 4| projecting laterally therefrom strikes anabutment 34 onthe detector lever 34. The position of the quadrant atthis time consequently depends on the pressure which has been acting onthe diaphragm boxes during the preceding interval of time.

The quadrant is locked in the position to which it is moved by thespring, there being for this purpose a lever 42 having a plurality ofteeth, held by a spring 43 in engagement with a toothed wheel 44 fixedto a pinion 45 in mesh with the quadrant 39. The teeth of the wheel 44and the detent lever 42 are of such configuration that the detent leverrestrains the wheel from rotating in one direction only. The lever 42 isconnected with a lever arm 46 resting on a cam 41 rotating with the disc26. When the lever is lifted by the cam 41 the lever 42 releases thewheel 44 and quadrant 39. The shaft 38 has fixed thereto a quadrant 48for actuating, by means of gears 49, 49*, a vertically reciprocatablerack 56 having at its upper end the style (not shown) which records thefluid pressure or degree of vacuum on the sheet 5.

At each revolution of the disc 26 the detector lever 34 is disengagedfrom the curved arm 33,

, which is thus able to assume a new position,

whereupon the lever 34 returns into" engagement therewith. The cam 41and lever 46 then disengage the lever 42 from the wheel 44 and releasethe quadrant 39, which assumes a posi'-' spring 40, so that the frictionincidental to the" movement of that style is overcome by the springalone and does not in any .way react on the setting of the mechanismactuated by, the fluid pressure. 7

The instrument described may with advantage, be used in connection withaircraft, for the purpose of obtaining a continuousrecord of chargingpressure or fuel consumption concurrent with a record of speed. j a

What I claim as my invention and desire to secure by Letters Patent ofthe United States is:

1. A' follow-up mechanism comprising an elastic diaphragm deviceresponsive to fluid pressure, an oscillating detector, a rotatabledriving element for said detector, an abutment adjusted by saiddiaphragm device in the path of said detector limiting the movement ofsaid detector in one direction, style actuating mechanism for recordingthe fluid pressure and an oscillating driver actuated by said drivingelement for actuating said style actuating mechanism, said detectorlimiting the movement of said driver in one direcabutment in the path ofa quadrant which is in- Y termittently releasedand is then moved by aspring'against said abutment thereby actuating said style actuatingmechanism.

5. A follow-up mechanism as set forth in claim 1v in which said abutmentcomprises a curved arm on a shaft rotatable by said diaphragm de viceand said detector comprises a lever carrying an abutment in the path ofa quadrant which is intermittently released and is then moved by aspring against said abutment thereby actuating said style actuatingmechanism, said quadrant f being locked by a ratchet'device which is putout 7 of action by a lever when said detector engages 'said first-namedabutment.

,tic diaphragm device responsive to fluid pres- 6. A follow-up.mechanism comprising an elassu're, an oscillating detector, a rotatabledriving element for said detector, an abutment adjusted by saiddiaphragm device in the path of said detector limiting the movement ofsaid detector in one direction, style actuating mechanism for' recordingthe fluid pressure, an oscillating driver actuating by said drivingelement for actuating said style actuated mechanism, said detectorlimiting the movement of said driver in one direction, said adjustableabutment being a curved arm on a shaft rotatable by; said diaphragmdevice, a quadrant, saiddetector being a lever carrying an abutment inthe path: of said quadrant which is intermittentlyreleased and thenactuated by a'spring up to said, abutment thereby actuating saidstyleactuating mechanism, said quadrant being locked ,byha' ratchet devicewhich is disabledwhen said, detector engages said first-mentionedadjustable abut,-

ment. I a 7. A follow-up mechanismcomprising an elastic. diaphragmdevice responsive to fluid pressure, an oscillating detector,'arotatable driving element for, said detector, an abutment adjusted bysaid diaphragm device in the path of said detector limiting the movementor'saidldetector in one direction, style actuatingmechanism forrecording the fluid pressure, an oscillating driver actuating by saiddriving elementfor actuating said style actuated mechanisnr'said'detector limiting the movement, of said driver in one direction, saidadjustable abutment comprising a shaft rotatable by said diaphragmdevice and a curved arm thereon, a quadrant, said detector comprising alever carrying an abutmentin the path of said quadrant which is intermittently released and it is 'then moved by a spring up, to saidabutment thereby actuating.

said style actuating mechanism, a ratchet de' vice for locking saidquadrant and a lever fordisabling said ratchet device when saiddetectorengages said first-mentioned adjustable abuts ment.

ERNST BAUMANN.

